A mobile telecommunication device, such as a cellular telephone or a police mobile radio, communicates with other telecommunication devices via transmission and reception of radio frequency (RF) signals with one of a plurality of base stations that is part of a wireless network telecommunication system. The overall telecommunication system may, of course, also include a wired portion. Using cellular telephones as merely one example, FIG. 1 illustrates the basic components of a typical cellular telephone telecommunication system 10. In such a system, the cellular telephone network comprises a plurality of stationary base stations 12a-12d geographically separated from each other. Each base station covers a small geographic area (or cell) 19 surrounding the base station 12. Cells 19 typically overlap with each other so as to assure full coverage of an overall geographic area. A cellular telephone, such as cellular telephone 14a, establishes contact and communicates with the base station that provides the strongest signal, such as base station 12a, via RF signals 16. The base stations are coupled to a wired communication network 18 that routes the call through the wired network 18 to another telecommunication device. The other telecommunication device may, for instance, be another cellular telephone 14b, in which case, the signals are routed from the wired network 18 to another cellular base station 12d that is close to the other cellular telephone 14b, where they are converted to RF signals 16 broadcast to the cellular telephone 14b. 
In order to provide an efficient communication system, it is important for the network as well as each cellular telephone to keep track of which cellular base station is closest to the telephone. Particularly, each telephone 14 should know which cellular base station 18 provides the strongest signal so that it can communicate with that particular base station so as to minimize the amount of power required to transmit to the network and to assure the highest quality connection. Also, the network must keep track of the base station that has the best communication link with each cellular telephone for the same reasons and also so that it can know which base station to route a call to when a call for a particular cellular telephone is made.
Hence, a cellular telephone 14 typically will wake up from a standby mode to listen for a page from the base stations at predetermined intervals. Specifically, during a page, the cellular telephone typically accomplishes three general tasks, namely, (1) monitoring the base station, (2) polling neighboring base stations, and (3) establishing a communication link if the telephone is initiating an outgoing call or is the intended recipient of an incoming call.
With respect to the first above-mentioned task, i.e., monitoring, the cellular telephone typically will have previously determined a default base station with which to communicate based on preceding pages, which would typically be the base station providing the strongest received signal strength for the cell phone. The telephone will The telephone will turn on its receive circuitry to listen for transmissions from the default base station to determine, for instance, if the base station in transmitting a signal indicating that the telephone has an incoming call.
With respect to the second general task performed during a page, i.e., polling, the telephone checks the signal strength of the default base station as well as any other base stations within range to assure that it is always talking to the base station with the strongest signal (presumably, although not necessarily, the closest base station). In a typical neighboring cell polling process, the telephone the telephone listens on the various frequencies that neighboring base stations may be transmitting on for signals from any base stations within range. The cellular telephone then determines the received signal strength of every base station that responds and determines if any of the responding base stations has a received signal strength greater than that of the default base station. Usually, if the telephone determines that there is a neighboring cell base station with a received signal strength greater than the default base station by some predetermined amount, the telephone will switch the default base station to the new base station. Usually, when a cellular telephone switches base stations, it registers with the new base station during the first page after the switch. Registration involves exchanging various information with the base station, such as transmitting to the base station its phone number, electronic serial number, and its home network ID, and receiving from the base station the local network ID (so that the telephone can inform its user whether the telephone is in a home cell or roaming).
The third task is only performed, if, in fact, a call is being initiated or received during a page. Particularly, if the user of the telephone is initiating a telephone call (or data link), then the telephone will also transmit to the base station, during the page, a request for a channel and the data necessary to place the call, such as the telephone number of the called party. Likewise, if a third party has called the cellular telephone (and the call has been properly routed through the wired portion of the telephone network(s) to the correct base station), the base station will transmit to the cellular telephone during the page certain data, such as a message indicating that the telephone has an incoming call and the telephone number of the calling party.
If, during a page, the base station informs the telephone that it has an incoming call, the telephone will issue a designated ring tone to inform its user of the incoming telephone call. The base station usually will provide a predesignated period within which the telephone may “answer” the call (e.g., 10 seconds). Also in accordance with conventional protocol. If the user takes the telephone off hook during the predesignated period provided by the base station, a communication channel with the base station will be set up and the call will be established.
The paging interval, i.e., the time between consecutive pages to a base station, for a typical cellular telephone is in the range of about 0.5-4 seconds and the page transmission itself typically may be about 25-100 milliseconds in duration. The paging interval generally needs to be this short because, in order to receive an incoming call in real time, the telephone must be in very frequent contact with the network so that there is not a long delay between the calling party placing the call and the called party phone ringing.
As previously noted, a cellular telephone page typically may consume about 25-100 milliseconds, of which approximately half is consumed monitoring the default base station (including initiation of a call if a call is being placed) and approximately the other half is consumed polling neighboring cells. During paging, the cellular telephone is consuming substantially more power than when it is in standby mode. Specifically, essentially all of the receive path circuitry, including filters and amplifiers are turned on and adjusted. In addition, the processor is processing data, such as the received signal strength data for all of the neighboring base stations and determining which provides the best signal. Paging is one of the biggest drains on a battery of a cellular telephone. A typical cellular telephone, for instance, may draw on the order of 25 to 50 times as much power from the battery when paging than when it is in standby. A common goal in the design of essentially all mobile telecommunication devices is to minimize power consumption so that the battery can last as long as possible between recharging and/or so as to reduce the size of the battery so that the telecommunication device can be made smaller and lighter.
Accordingly, it is an object of the present invention to minimize power consumption in a wireless communication device.
It is another object of the present invention is to decrease the paging frequency (increase the paging interval) in a wireless communication device.